Physico-chemical Properties of Defatted Sesame and Moringa Seeds
Chapter One
Objectives of the Study
The main objective of this study is to examine and determine the physicochemical properties of Moringa oleifera and Sesame indicum, L seeds.
CHAPTER TWO
LITERATURE REVIEW
Overview of Sesame (Sesamum indicum L.)
Sesame (Sesamum indicum L.) is one of the world’s important oil crops. Its primary marketable products are the whole seeds, seed oil and meal. While sesame seeds have been grown in tropical regions throughout the world since prehistoric times, traditional myths hold that their origins go back even further. According to Assyrian legend, when the Gods met to create the world, they drank wine made from sesame seeds. These seeds were thought to have first originated in India and were mentioned in early Hindu legends. In these legends, tales are told in which sesame seeds represent a symbol of immortality. From India, sesame seeds were introduced throughout the Middle East, Africa and Asia. Sesame seeds were one of the first crops processed for oil as well as one of the earliest condiments (de Carvalho et al., 2001). These seeds were brought to the United States from Africa during the late 17th century. Currently, the largest commercial producers of sesame seeds include India, China and Mexico
Sesame seeds add a nutty taste and a delicate, almost invisible crunch to many Asian dishes. They are also the main ingredients in ‘tahini’ (sesame seed paste) and the wonderful Middle Eastern sweet called ‘halvah’. Sesame seeds may be the oldest condiment known to man dating back to as early as 1600 BC. They are highly valued for their oil which is exceptionally resistant to rancidity. “Open sesame”, the famous phrase from the Arabian Nights, reflects the distinguishing feature of the sesame seed pod, which bursts open when it reaches maturity. The pods are tiny, fl at ovals, measuring about 3 mm long. Seed color can vary, though they are usually beige or creamy white when husked. Sesame oil, other than its use as cooking medium, has certain industrial applications as it is used to make hair oil, hydrogenated oil and certain medicines (Salunkhe et al., 2001; Suja et al., 2004; Quasem et al., 2009). The present review highlights the food/nutritional, medicinal and pharmaceutical uses of sesame seeds.
Plant habitat and characteristics
Sesame, a member of Pedaliaceae family, is an annual shrub with white bell-shaped flowers with a hint of blue, red or yellow with or without branches (Martin and Leonard, 2007). It is grown for the production of seeds that are rich in oil content. It comes in a variety of colors, creamy-white to charcoal-black. In general, the paler varieties of sesame seem to be more valued in West and Middle East, while the black varieties are prized in the Far East. Sesame is found in tropical, subtropical, and southern temperate areas of the world, particularly in India, China, South America and Africa. It has utmost economical importance and is primarily grown by small farmers in developing countries. The plant grows best in tropical climates, sandy, well drained soil with hot climate and moderate rainfall. It is propagated by seed sown in spring and takes about four months for the seeds to ripen fully.
Sesame is a tropical herbaceous annual that grows 1-2 m tall. The plant has an unpleasant odor. The leaves vary from ovate to lanceolate and are hairy on both sides. The flowers are purple to whitish, resembling foxglove, followed by 3 cm capsules/fruits containing numerous seeds (McCormick, 2001). Each plant may bear 15-20 fruits, which contain 70-100 seeds. It matures in 80–180 days when the stems are cut and hung upside down for the ripe seeds to fall out to be collected on mats. Mechanical harvesting is also used, with total worldwide production of almost four billion pounds annually.
Products and cultivation of sesame
Sesame is grown for its seeds and the primary use of the sesame seed is as a source of oil for cooking. The young leaves may also be eaten in stews and the dried stems may be burnt as fuel with the ash used for local soap making but such uses are entirely subordinate to seed production. The crop of sesame is commercialized in a number of forms. Most sesame seeds are processed directly into oil by the grower or within the producing region but are also sold in various stages of processing, for various uses, such as meal, paste, confections and bakery products (Salunkhe et al., 2001). Once harvested, the seeds are cleaned and dried to about 8% moisture and then stored before crushing. The seeds are typically crushed intact for the oil. This, however, yields a meal that is bitter and somewhat indigestible due to the presence of the fibrous husk. As such the meal is only useful as cattle feed. The quality of the meal can be improved by removing the seed coat, dehulling, before crushing (Morris, 2002).
In India, where sesame meal is an important food, this process is a standard feature of an oil extraction plant. The meal is remarkable for its high protein content, which again is rich in methionine and tryptophan. Since these amino acids are missing from a number of other sources of vegetable protein, such as soy, sesame meal or fl our can be added to recipes to give a better nutritional balance to health food products (Prakash, 2005; Quasem et al., 2009). Dehulling is also important for the production of the ground seed pastes such as tahini and for confectionery uses. The dehulled seeds are extensively used in the ground form where they comprise the base material of tahini, a paste used as an ingredient in Eastern Mediterranean and Middle Eastern foods. The seeds, hulled or dehulled, roasted or raw are now widely used in the European and North American bakery industry as a garnish on bread products. Dehulling has always been a major problem for the sesame industry and a variety of solutions have been sought. The most basic approach is largely manual: the skins are rubbed off the wetted seed by hand. Mechanical techniques now use a similar combination of wetting and rubbing.
Alkali treatment is also used to strip the hull and this tends to result in a whiter seed. The dehulling process, no matter what the method, always involves wetting the seed, which leads to considerable drying costs. As a result, the price of de-hulled seed is at least 30% above the natural type (Morris, 2002). Dehulling is said to reduce the storage ability of the seed, particularly in hot climates. Only a small proportion of the global sesame harvest enters International trade. For the most part, the oil is expressed locally and used locally for cooking or the seeds themselves are eaten, particularly after being fried. The oil is also useful in the industrial preparation of perfumery, cosmetics (skin conditioning agents and moisturizers, hair preparations, bath oils, hand products and make-up), pharmaceuticals (vehicle for drug delivery), insecticides, and paints and varnishes. However, all of these uses are comparatively insignificant in terms of the quantities used (Chakraborthy et al., 2008).
CHAPTER THREE
MATERIALS AND METHODS
Materials
- oleifera and Sesame indicum was purchased at the main market (Oja Oba) in Owo, Ondo State. The chemicals and wares used in analyzing the seeds from M. oleifera and S. indicum were gotten from microbiology and chemistry laboratory of Food Science and Technology, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria.
Methods
Preparation of moringa and sesame seeds
The Moringa and sesame seeds were separated from the chaffs and other impurities, the seeds of M. oleifera and S. indicum were dried at 35˚C – 40˚C in van air circulating oven till dryness. The dried seeds were crushed in a knife mill to obtain homogenous seed particles. Subsequently, the crushed seeds were mechanically pressed to extract the edible oil then filtered and kept in dark bottles with airtight lids under cooling temperature until being used. Dried raw seeds was collected and kept under cooling for analysis.
CHAPTER FOUR
RESULTS AND DISCUSSION
Results
Table 4.1: Proximate properties of moringa and sesame seeds
CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
Conclusion
The Moringa and sesame seed is a promising seed with many nutritional qualities. The findings of this study shows that the moisture content of sesame is lower compared to Moringa seeds, which means a larger and stable shelf life of sesame seed, the fat content of Sesame seed is way higher than that of Moringa seed, indicating that sesame seed has higher oil content than Moringa. Although, the protein, fibre and carbohydrate content of Moringa seed is more than Sesame seed. Both samples are good for omsumption and can be used interchangeably.
Recommendation
For further investigation, more research should be conducted In order to enhance and retain the nutritional qualities of the seed or oil during processing. Methods to lower the moisture content of Moringa seed should be adopted for storage and future use of Moringa seeds.
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